Datasheet

 2012 Microchip Technology Inc. Preliminary DS41652A-page 23
PIC16F527
4.8 Direct and Indirect Addressing
4.8.1 DIRECT DATA ADDRESSING: BSR
REGISTER
Traditional data memory addressing is performed in
the Direct Addressing mode. In Direct Addressing, the
Bank Select Register bits BSR<1:0>, in the new BSR
register, are used to select the data memory bank. The
address location within that bank comes directly from
the opcode being executed.
BSR<1:0> are the bank select bits and are used to
select the bank to be addressed (00 = Bank 0, 01 =
Bank 1, 10 = Bank 2, 11 = Bank 3).
A new instruction supports the addition of the BSR
register, called the MOVLB instruction. See
Section 13.0 “Instruction Set Summary” for more
information.
4.8.2 INDIRECT DATA ADDRESSING:
INDF AND FSR REGISTERS
The INDF Register is not a physical register.
Addressing INDF actually addresses the register
whose address is contained in the FSR Register (FSR
is a pointer). This is indirect addressing.
Reading INDF itself indirectly (FSR = 0) will produce
00h. Writing to the INDF Register indirectly results in a
no-operation (although Status bits may be affected).
The FSR is an 8-bit wide register. It is used in
conjunction with the INDF Register to indirectly
address the data memory area.
The FSR<6:0> bits are used to select data memory
addresses 00h to 1Fh.
FSR<7> is unimplemented and read as ‘0’.
A simple program to clear RAM locations 10h-1Fh
using indirect addressing is shown in Example 4-1.
EXAMPLE 4-1: HOW TO CLEAR RAM
USING INDIRECT
ADDRESSING
MOVLW 0x10 ;initialize pointer
MOVWF FSR ;to RAM
NEXT CLRF INDF ;clear INDF
;register
INCF FSR,F ;inc pointer
BTFSC FSR,4 ;all done?
GOTO NEXT ;NO, clear next
CONTINUE
: ;YES, continue
: